Universal biomass refinery

ABSTRACT

The invention is directed to a process for refining prepared biomass to produce hemicellulose hydrolyzates, cellulose of sugars involving the perforate at least a portion of the cells of the prepared biomass prior to hydrolyzing the biomass, reclaiming the catalysts used in hydrolysis, and drying the hydrolysis using reclaimed heat from previous steps in the process.

FIELD OF THE INVENTION

The present invention relates generally to fast and energy efficientmethods of refining biomass.

BACKGROUND OF THE INVENTION

Improvements to refining biomass on a large commercial scale wouldprovide numerous benefits. The market for products of biomass refinementis in the billions of dollars per annum. Protein is a dietaryrequirement, but is insufficiently met by many populations, including inthe tropics, an area where biomass can best be grown. Further, replacinggrain fed to cattle with digestible fibre will make more corn availablefor human consumption worldwide. The market for sugars which can beconvened into biofuels, chemicals and plastics is in the lens, possiblyhundreds of billions of dollars per annum. Refining of biomass intosugars therefore represents a useful application. Given how readilyavailable biomass is, the creation of a large scale commercial biomassrefining process could provide a significant energy source worldwide.

To date, a large scale commercial process does not exist that convertsthe ligno-cellulose components of biomass to sugars. Concentrated acid,high-temperature dilute acid combinations, steam, moderatetemperature/neutral pH dry grinding, strong alkali, liquid anhydrousammonia, high water ratios of lime, conically-shaped rotor-stator tools,laboratory sonicating devices, liquid stream, high-shear, and cavitatingdevices have been used to attempt to refine biomass commercially.However, none of these processes have been scaled up to refine biomasseconomically.

The methods available that make use of acid require that the hydrolysiseither occurs at high temperatures or uses high concentrations of strongacids which are difficult to remove from the product. Both of theseissues lead to high production costs.

There is a demand for a lower energy, thermal-chemical process capableof complete or selective biomass refining with high catalyst recoverywhich does not requiring enzymes for cellulose hydrolysis or one whichenhances enzymatic hydrolysis of cellulose, and which can effectivelyhydrolyze biomass into dry sugar solids without major degradation ofsugars.

SUMMARY OF THE INVENTION

The present invention provides a thermal-chemical process for therefinement of biomass into useful products.

The invention is directed to a process for refining prepared biomass toproduce a slurry having hemicellulose hydrolysis in solution comprisingthe following steps:

-   -   Extracting trace sugars and extractables from the prepared        biomass in a catalyst solution by applying mechanical shear or        cavitation to create a first slurry, the first slurry having a        first solids portion comprising hemicellulose and cellulose, and        a first liquid portion which comprises extractables in solution,        to perforate at least a portion of the cells of the prepared        biomass;    -   Mechanically separating the first solids portion for the first        liquid portion; and    -   Hydrolyzing hemicellulose in the biomass by applying mechanical        shear or cavitation to the biomass in solution with a catalyst        to create a second slurry having a second solids portion        comprising cellulose, and a second liquids portion comprising        hemicellulose hydrolyzates in solution.

The process may further comprise the steps of:

Mechanically separating the second solids portion from the second liquidportion, and

Hydrolyzing cellulose in the second solids portion in the presence of atleast one strong acid to produce solution comprising sugar.

The process may also include the step of hydrolyzing the lignin in thefirst solids portion or the second solids portion prior to the step ofhydrolyzing the cellulose, in a catalyst solution by applying mechanicalshear or cavitation; and the step of mechanically separating the liquidportion of the hydrolyzed lignin from the first solids portion or thesecond solids portion.

The process may also comprise the step of drying the solution comprisingsugar by

-   -   Introducing the solution comprising sugar into an expansion        chamber with means for heating the expansion chamber to a        temperature above the boiling point of the solution comprising        sugar, and    -   conveying sugars and vapors out of the expansion chamber into a        solids-vapor separation zone with vapors rising towards a heat        exchanger, while sugars are further conveyed into a final sugar        dryer        wherein the vapors going through the heat exchanger exchange        heat with the means for heating the expansion chamber to        maintain the temperature of the expansion chamber above the        boiling point of the incoming sugar solution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a process for refining biomass to protein extractables,tannins, hemicellulose sugars, lignin, cellulose, and glucose,illustrating multiple process options for supplying dry feedstock tohemicellulose hydrolysis, and multiple cellulose hydrolysis options.

FIG. 2 depicts two pathways for strong acid hydrolysis of cellulose.

FIG. 3 depicts options for one stage strong acid hydrolysis.

FIG. 4 depicts a heat exchanging dryer method.

DETAILED DESCRIPTION

The invention is a process for refining biomass to produce refinablesugars from hemicellulose and cellulose fractions of biomass, and mayalso produce protein (or protein derivative polypeptides or aminoacids), lignin, minerals, tannins, cellulose microfibers and cattlefeed. The process may be used to process waste biomass into feedstockfor chemicals and fuels. The described methods make use of recycledcatalysts, including acetic acid derived from biomass, and are useful toproduce economically viable products from biomass, including dry sugars,protein derivatives, cellulose microfibers, lignin, cattle feed, tanninsand other products while providing new avenue for waste conversion.

The process may isolate lignin in one of three stages. The invention mayalso include producing dry cellulose microfibres. Alternately, acellulose-lignin product can be produced.

The process may comprise many or all of the following steps, dependingon the desired output products and recycling measures taken.

-   -   (1) Mechanically reducing biomass to smaller particle size and        surface area;    -   (2) Adding a catalyst, heat, high shear and/or cavitation to        hydrolyze a small portion of each biomass cell wall to enhance        mechanical extraction of liquids and extractables;    -   (3) Mechanically separating the first slurry into biomass solids        and a first liquid extraction containing hemicellulose derived        hydrolyzates, protein and protein derivatives, tannins and other        extractable products;    -   (4) Combining first liquid extraction with more new biomass;    -   (5) Repeating steps 2 and 3 to build up the concentration of        extractable products in the first liquid extraction;    -   (6) Drying the mechanically separated residual biomass solids,    -   (7) Diverting a side stream of a first extractables liquid        concentrate;    -   (8) Boiling the side stream of first liquid extractables,        optionally using the heat exchanging dryer method described        below;    -   (9) Recovering extractable products from first liquid extraction        as dry product;    -   (10) Combining acid catalyst (which may be recycled from step        (15)) with dry residual biomass microfiber solids (from step        (6)) in a second slurry for hemicellulose hydrolysis;    -   (11) Adding further mild and/or strong acids catalyst to the        second slurry, preferably while applying cavitation as needed,        and maintaining temperature up to the boiling point of the        catalyst;    -   (12) In the case where the system is initially building up a        concentration of sugars in solution before reaching a steady        state sugar concentration, mechanically separating the second        slurry into un-dissolved cellulose-lignin solids and a liquid        second slurry containing hemicellulose hydrolyzates and other        extractables;    -   (13) Combining the second liquid extraction (from step (12))        with more residual biomass solids (from step (6)) and repeating        steps (9)-(12) to further build up hemicellulose sugar        hydrolyzates and extractables in the second liquid extraction;    -   (14) Separating the cellulose-lignin solids (which may be        collected in step (12)) from any residual acid catalyst by        boiling or evaporating the acid catalyst solution into vapors;    -   (15) Condensing acid catalyst vapors (from step (14)), recycling        them for use in further hemicellulose hydrolysis of dry residual        biomass solids in step (9), which may employ the heat exchanging        dryer method described below;    -   (16) Boiling or evaporating a stream of the second liquid        extraction to produce dry hemicellulose sugars and other        extractables (which may be used in step (11)), to control second        liquid portion viscosity, and to separate the acid catalysts        from the dry hemicellulose sugars and extractables as vapors,        which may employ the heat exchanging dryer method described        below;    -   (17) Condensing acid catalyst vapors (from step (16)) and        optionally recycling for their use in further hemicellulose        hydrolysis of dry residual biomass solids in step (9) by way of        condensing through heat exchanger into liquid, which may employ        the heat exchanging dryer method described below;    -   (18) Creating a third slurry by combining a hot water-alkaline        chemical solution with the mechanically-separated and dried        cellulose-lignin solids (from step (14)), causing a liquefaction        of lignin and creating a third biomass solids comprised        principally of cellulose;    -   (19) Mechanically separating the third slurry into cellulose        solids and liquefied lignin and water-alkaline chemical        solution;    -   (20) Optionally, the following steps can be employed to treat        the separated cellulose solids for further use:        -   a. Drying the cellulose solids of all or substantially all            water to produce a cellulose product, or dried except for            any water necessary for downstream hydrolysis if applicable;    -   b. Washing cellulose microfibres with water to remove any        residual liquefied lignin, mechanically separating and drying        the cellulose, or keeping the washed cellulose in solution or        wetted form.    -   (21) Combining the liquefied lignin and water-alkaline chemical        solution (from (19)) with more dried cellulose-lignin solids        (from (14)) and repeating steps (18)-(19) to further build up        liquefied lignin product and to recycle alkaline catalyst;    -   (22) Extracting liquefied lignin from the liquefied lignin and        water-alkaline chemical solution by adding acid to precipitate        the lignin;    -   (23) Mechanically filtering lignin solids from the water,        optionally using sparging bubbles to float and concentrate        lignin before filtration, then drying lignin by boiling the        residual water-liquid from the lignin, then applying filtered        water into step (18);    -   (24) Optionally creating a fourth slurry of cellulose and water        for the hydrolysis of cellulose into glucose by combining        cellulose (from (20)) with either;        -   a. Concentrated strong acid and sufficient water to effect            hydrolysis of cellulose, and keeping the slurry at one            atmosphere pressure and at least one degree above freezing;            or        -   b. Water and dilute strong acid, and keeping the slurry at a            temperature sufficient to hydrolyze the cellulose to glucose            (170-260 degrees Celsius);        -   c. Water and dilute strong acid and a concentrated mild            acid, keeping the slurry at a temperature sufficient to            hydrolyze the cellulose to glucose (170-250 degrees            Celsius);            allowing for a residence time from 0.0001 second to 30 days;    -   (25) Adding additional cellulose (from (20)) to the cellulose        slurry, one or more times to increase glucose concentration in        the slurry; and, if required, more concentrated or dilute strong        add (as appropriate in either (24a) or (24b));    -   (26) Optionally applying high shear and/or cavitation during        hydrolysis    -   (27) Flash boiling the slurry (from (23)) to yield glucose, and        optionally drying the glucose by:        -   a. increasing pressure up to 20,000 psi, then instantly            releasing pressure while adding heat sufficient to rapidly            boil all remaining liquid catalyst during pressure release;            and/or        -   b. Optionally, applying a vacuum in combination with the            pressure release and less heat (under 120 degrees Celsius),            in order to boil acid catalysts at lower temperature, better            preserving glucose from hydrolysis; and/or        -   c. Using the heat exchanging dryer method described below.            More details on this method and its various options are            described in the sections which follow.

Where it appears in the specification, “extractables” is intended torefer to tannins, protein, chlorophyll, and other chemical compoundsthat are soluble in water which are readily available for extraction instep 5 above. The extractables may also contain dissolved sugars.

The acetic acid may be produced as a product of hydrolysis, and isrecovered and used as the catalyst in any stage which requires it.

As used in this specification, “sugars” include monosaccharides (e.g.,glucose, fructose, galactose, arabinose), disaccharides (e.g., sucrose,lactose, maltose), and oligosaccharides and more rarely, trisaccharides,of each monomer sugars where appropriate.

Preparation of Biomass

As shown in FIG. 1, the particle size of wet or dry biomass is reducedto increase biomass feedstock density, manageability, and to createsurface area to allow passage through even smaller portals withindownstream process machines designed to further reduce particle size inorder to maximize solids concentration and surface area for overallprocess efficiency with heat and chemicals.

Dry biomass (1 a) is processed by at least one of the following:chopped, milled, ground and/or pulverized by mechanical methods tocreate small particles and high surface area prior to hydrolysis. Hogmills, hammermills, double-disk attrition mills, machete, or any drygrinding method known to those skilled in the art can be utilized toreduce particle size for further processing. Other methods includingprimitive chopping with machete, shredding, chopping or grinding systemspowered by animals, water, wind or any cutting method device whichreduces dry biomass particle size by slicing, crushing or choppingbiomass into smaller particles are applied to prepare for furtherprocessing.

Wet biomass (1 b) is chopped to small particles using a forage harvestersuch as those manufactured by John Deere, Case, Gleaner and others,and/or any method including, but not limited to primitive chopping withmachete, shredding, chopping, blade cut or grinding systems or anycutting method device which reduces wet biomass particle size byslicing, crushing or chopping biomass into smaller particles than theirnative size, with methods powered by man, animals, water, wind,electricity, steam or any power source are applied to prepare biomassfor further processing and to enhance downstream efficiency.

The term “prepared biomass” means biomass prepared in accordance withthe foregoing paragraphs, and any biomass prepared by similar methods orsystems known in the art.

Creating the First Slurry

Wet or dry biomass, having been reduced from native harvested or cutsize, is further processed by adding sufficient water to create a firstslurry with a low enough viscosity and whose biomass particles are smallenough to foe able to pump by centrifugal pumps.

Within the slurry created, particles are reduced to smaller particles ina sequence of low to high shear slurry devices, followed by cavitation(1 a, 1 b). The range of slurry passages within slurry devices isbetween 50 millimeters and 0.25 millimeters, the difference betweenregular shear turbulent flow and cavitation being rate of passage, holesize bored into rotors and/or stators, and related pressures; highpressure and vacuum in the case of cavitation. The temperature range forapplying shear and/or cavitation to water or acid-water slurry is atleast 1 degree Celsius above freezing point of slurry, up to but not atthe boiling of the slurry at one atmosphere, or a higher temperatureunder pressure. Distinct from the slurry entering a cavitation devicewithout bubbles, cavitation creates a localized boiling of the slurrywater in producing first stage of cavitation: bubbles, which thancollapse emitting a high speed shock wave; both stages causing extremedestruction of biomass particles from within and without the biomasssurface, resulting in ever smaller and more disrupted particles.

In one embodiment, the temperature and boiling point of the slurry isincreased by employing high pressure vessels and added heat, withtemperatures being increased up to 170 degrees Celsius.

In one embodiment of the slurry, mild and strong acids with boilingpoints under 120 degrees Celsius can each be added in various ratiosolution to biomass with a combined total up to 99.999%, or high boilingpoint acids such as sulfuric acid can be added to the slurry, preferablyin the range of 0.0001% to 1% in order to accelerate the rate of, and toincrease the degree of extraction of extractables.

Optionally, within the shear and cavitation treated biomass slurry, analkaline chemical such as lime, sodium hydroxide or any other suitablebase chemical, is added at ratios between 0.0001% to 10% by weight tonet biomass in slurry, in order to accelerate and enhance extraction oftannins, fats, oils and other trace biomass components, protein, andprotein derivatives such as polypeptides and/or amino acids(extractables), and sugars including glucose, arabinose, galactose,mannose, disaccharides and trisaccharides of the same sugars, in biomasswhere such components exist, and have not been removed with anotherprocess or process step prior to the present invention.

In either application of alkaline or acid as described immediatelyabove, controlled conditions in the ranges described herein, of catalystconcentration, temperature, time and the application of high shearand/or cavitation can produce a controlled, limited, hydrolysisresulting in cell compromise to enhance mechanical extraction of liquid.

Cell perforation is enhanced with the addition of acid or base chemicalscombined with high shear and/or cavitation, which lowers processviscosity and increases process capacity for higher solid loadings asliquid normally trapped inside biomass cells are released. Removingwater from perforation cells with mechanical pressure correspondinglylowers drying costs of products. A chemical optionally applied in thefirst slurry produces varying degrees of hemicellulose hydrolysis,determined by combinations of residence time, temperature, and chemicalloading. When a separate protein and tannin product extraction isformulated for marketing, the slurry containing no additional chemicals,or minimal chemicals as low as 0.0001% to the slurry, at varioustemperatures up to the boiling point of water, at one atmosphere or athigher temperatures under pressure, is applied to accelerate and enhancetheir extraction with minimal hemicellulose components extracted. Onepreferred temperature for protein extraction is up to 120 degreesCelsius.

This step is performed long enough to perforate at least a portion ofthe cells of the biomass, such as at least 30%, and preferably 70% ormore preferably 90% of the cells. The greater percentage of cellsperforated at this stage, the more water can be extracted from thebiomass at this stage.

Mechanical Separation of First Slurry and Solids

The first slurry processed by shear and/or cavitation and chemicals isthen mechanically pressed (2, 4) to separate liquid from biomass, totypically 50%-65% liquid relative to biomass, but can be between 0% and99.99% depending on the type of mechanical press device, pressuresetting, temperature, type and degree of chemical added if any, degreeof biomass cell disruption and release of liquid from cells whenmechanically pressed, and other factors.

Liquid pressed by a mechanical device is recycled (4) to supply liquidrequired to conduct slurry processing at low, medium, high shear, andcavitation (1 a, 1 b), and to concentrate extractables. Mechanicalseparation devices that can be used (2, 4, 11, 18) include but are notlimited to centrifuge, a screw press, a belt press, a plate and framepress, a roller drum filter with pressure belt or any solid-liquidmechanical separation device known to those skilled in the art.

First Liquid Extraction

The first liquid extraction produced from mechanical separation of thefirst slurry option without adding chemicals, is mixed with more newbiomass in repeated cycles (3,4), which, as extraction of extractablesproceeds, re-generates the first slurry with increasing concentrationsof tannins, protein, polypeptides and amino acids. For more efficientextraction of extractables; chemical catalysts are added to the slurry,producing, in addition to the extractables described above, variouslevels of hydrolyzed hemicellulose derivative sugars which can be alsoextracted.

A preferred first slurry concentration and viscosity is one in which ahigh percentage of extractables are released and separated from solids,while the slurry can still be pumped with a centrifugal pump, or if ahigh level of hydrolysis can be achieved at even higher viscosity, ascrew type, progressive cavity pump with product concentration reaching7%-60% before boiling for separation and concentration.

When a preferred concentration of extractables is reached, in excess of7%, a side stream of first liquid extraction is diverted from therecycle stream after mechanical pressing (4, 6).

Heat from any source is applied to the diverted first liquid extraction(7). The heat can be provided from internally cycled sources, orsystem-produced steam from burning extracted lignin or from burning anysource of fuel. Heat can be in the form of steam and/or indirect heatthrough double-wall pipes or tanks. Dissolved extractables are recoveredas a dry product (8), or optionally for further processing, at variouslevels of residual water. Optionally, vacuum can be applied in order tolower drying temperature in order to protect hydrolyzed or otherwiseextracted biomass components, such as protein and/or proteinderivatives. Boiling temperature required correlates to the specificcombination of water, and acid or base, and their respective boilingpoints. Alternatively, the heat exchanging dryer method described belowmay be employed here.

Drying Mechanically Separated Biomass Solids

The mechanically separated biomass solids in the press cake are dried inany type of suitable drying system known to those skilled in the art,including direct or indirect heating systems using internally extractedlignin, external solid or liquid energy sources, or solar energy (5).

The drying process is controlled to produce dry biomass or optionallybiomass which contains water to achieve specific catalyst/water contentrelative to acid or base chemical catalysts in downstream stages of thepresent invention (9).

Hydrolysis water can be provided through partially dried biomass, oradditional water can be injected into the first hydrolysis stage from aseparate source, with biomass entering in substantially dried form, orpartially wetted form.

Continuous Hemicellulose Hydrolysis Process

Preferably, the process uses a continuous hemicellulose hydrolysisprocess.

This step in the process requires combining an acid catalyst (which maybe recycled from step (14)) with dry residual biomass solids (from step(5)) in a second slurry for hemicellulose hydrolysis.

In one embodiment of this step, a strong acid in concentrations above0.0001% by mass is combined with dry residual biomass solids in acontinuous hemicellulose hydrolysis process.

In another embodiment of the process, a catalytic liquid containingacetic acid at a concentration above 0.001% is employed, combined with astrong acid in concentrations above 0.0001%, provided that the minimumwater level is still maintained at that required for hemicellulosehydrolysis to occur in producing sugar concentrations above 7%.

However, the process also involves continually adding dried or highsolids biomass [8] while maintaining a high sugar product slurryconcentration of at least 7% and up to 80% by mass.

This continuous process further involves continually mechanicallyseparating and recycling extractives from the product slurries, andapplying those recycled extractives and catalysts to hemicellulosehydrolysis or fresh incoming biomass going into hemicellulosehydrolysis. The process also involves continually producing a secondaryslurry in which solids are mechanically separated slurry comprising aproduct slurry which may be dried to separate out hemicellulosehydrolyzates. When acetic acid is applied, acetic acid is added to therecycled slurry as it is extracted through hydrolysis of fresh biomass.As required, the catalysis may be replenished from secondary sources tomaintain specified ratios of acetic acid and other acids As hydrolysisprogresses, additional biomass (12) and any additional necessary waterfor hydrolysis from new biomass or from any water source, is injectedinto the batch or continuous hydrolysis tank, pipe or other hydrolysisvessel until a combination of the following is achieved:

-   -   All or substantially all hemicellulose is hydrolyzed at maximum        viscosity which centrifugal pumps, high shear and cavitation        devices can pump the solids-containing slurry being treated; or    -   Hydrolysates have reached maximum possible concentrations and        viscosity for pumping.        Viscosity is maintained for optimized pumping and/or high shear        treatment (Mixing at higher viscosity is achieved using suitable        mixing solutions known to those skilled in the art, including        screw type devices [11-2]).

Hemicellulose Hydrolysis Batch Process

This step in the process requires combining an acid catalyst (which maybe recycled from step (14)) with dry residual biomass solids (from step(5)) in a second slurry for hemicellulose hydrolysis. In one embodimentof this step, dilute strong acid, or dilute strong acid and concentratedacetic acid, are combined with dry residual biomass solids in a batchhemicellulose hydrolysis process employing one or more trains of slurry.

In an embodiment of the process, a catalytic liquid containing aceticacid at a concentration above 0.001% is employed, combined with a strongacid in concentrates above 0.0001% provided that the minimum water levelis still maintained at that required for hemicellulose hydrolysis tooccur in producing sugar concentrations above 7%.

Residence times for the hydrolysis are between 0.001 seconds and 30days, while providing quantitative or nearly quantitative hydrolysis.

The catalytic acid liquid temperature with each catalyst formula isestablished up to, but not at the boiling point of the catalytic liquid.Higher temperatures up to 220 degrees Celsius can be used by providinghigh pressure vessels with pressure corresponding to specific catalystsolution requirements to prevent boiling.

Multiple trains of the same batch process may operate in sequence tosupply steady creation of hemicellulose hydrolysates of sugar, protein,minerals, some lignin and other hydrolysates, and to reduce residencetime for circulating sugars to insure qualify of sugars.

Mechanical Separation of Residual Cellulose-Lignin

After hemicellulose hydrolysis is complete, the second liquid extractioncontaining hemicellulose sugars and other extractables is separated fromthe solids portion containing cellulose-lignin solids (11). Mechanicalseparation devices that maybe employed include a centrifuge, a screwpress, a belt press, a plate and frame press, a roller drum filter withpressure belt or any solid-liquid mechanical separation device known tothose skilled in the art.

Mechanically separated cellulose-lignin biomass may be completely dried(13) applying heat, with recycled, condensed catalyst liquid beingapplied to incoming biomass or into the hemicellulose hydrolysis vessels(14). Optionally, the catalyst liquid may be condensed using the beatexchanging dryer method described below.

Upon separation, the following occurs with the liquid second extractioncontaining hydrolyzed hemicellulose sugars and other extractables:

-   -   1. Liquid second extraction and acid catalysts are recycled into        hemicellulose hydrolysis (12)    -   2. A build-up of extractables occurs from repeating the addition        of new biomass, hydrolysis of hemicellulose, mechanical        separation and recycling of catalyst and liquid product until        product concentration is above 7%    -   3. When appropriate, a stream of liquid second extraction        containing hemicellulose extractables is diverted and heat is        applied to boil off the acid catalyst and produce dry        hemicellulose extractables (15). The heat exchanging dryer        method described below may be employed here.    -   4. Acid catalyst condensed from boiling of liquid second        extraction are applied to        -   a. Hemicellulose hydrolysis directly (9), or        -   b. Incoming biomass (1 a, 1 b).

Lignin Extraction

If lignin has not been extracted prior to, or with hemicellulose, thecellulose contains lignin in various ratios depending on biomass typeand original lignin content.

Dried cellulose-lignin microfibres from the hemicellulose drying system(13) may be removed from the dryer and introduced into a ligninhydrolysis pipe or tank. The lignin may then be mixed with recycledhydrolyzed lignin alkaline chemical slurry (17, 20), optionally treatedwith high shear and/or cavitation The resulting slurry may then betreated either at one atmosphere from one degree Celsius above freezingup to but not at the boiling point of the alkaline-water hydrolysissolution, or treated at higher pressures and temperatures up to but notat hydrolysis temperatures of the cellulose fraction of thelignin-cellulose microflbres, which is preferably approximately under170 degrees Celsius.

When all or substantially all lignin is liquefied in start-up,mechanical separation is applied to the slurry to separate the liquefiedlignin and alkaline catalyst solution from residual cellulose (18). Newcellulose-lignin and make-up alkaline catalyst may be added to build upproduct concentration in start-up to achieve maximum productconcentration (20) while mechanical separation is applied repeatedlyuntil maximum liquefied lignin slurry viscosity is reached inmaintaining viable pumping, thereby liquefying a high percentage oflignin. Pumping of lignin slurry can be provided by centrifugal or screwpumps, high shear and/or cavitation devices. If the process is operatingin a batch configuration, as outlined above, when the optimalconcentration of lignin product is reached, the entire liquefied ligninslurry is processed to recover lignin by boiling off water (22).Optionally, the pH of slurry can be neutralized before any mechanicalseparation occurs in order to precipitate lignin.

If the process is operating in a continuous lignin liquefying process, asecondary stream of liquefied lignin is pH adjusted with acid toprecipitate the lignin. Optionally a sparging device producing bubblesis applied to lift and concentrate the lignin, lignin is mechanicallyseparated then boiled to separate and to dry water from lignin toproduce a dry lignin (22). In this case, the primary liquefied ligninstream and catalyst continues to be recycled as fresh cellulose-ligninand make up alkaline chemical is applied (20) until the liquefied ligninproduct reaches an optimal viscosity and product concentration, beyondwhich viscosity is too high for pumping. Optionally, a wash cycle orcycles using water can be applied to remove more lignin from residualcellulose solids.

Mechanically separated cellulose may be dried (19) to a percentage ofsufficient moisture for hydrolysis in concentrated, strong acidhydrolysis (23 a), or may be mixed with water to form a slurry for lowconcentration, strong acid hydrolysis (23 b).

Cellulose Hydrolysis

In the process, the cellulose may be hydrolysed into glucose as follows.A cellulose slurry for the hydrolysis of cellulose into glucose may beformed by combining dry or mostly dried cellulose (from (19)) witheither:

-   -   Concentrated strong acid, in which case the slurry is kept at        one atmosphere pressure and at least one degree above freezing,        or    -   Water and dilute strong acid, in which case the slurry is kept        at a temperature sufficient to hydrolyze the cellulose to        glucose (i.e. 170-250 degrees Celsius).    -   Water and dilute strong acid and a concentrated mild acid,        keeping the slurry at a temperature sufficient to hydrolyze the        cellulose to glucose (170-250 degrees Celsius);        Hydrolysis will occur over a period of time, preferable over a        period of 0.0001 seconds to 30 days.

In one embodiment of the process, a strong, preferably low boiling pointacid, in concentrations from 0.001% to 10%, preferably less than 1%, andwater, is applied to the cellulose extracted from the lignin extractionstep described above (23 a).

In another embodiment, a strong, preferably low boiling point add inconcentrations from 0.001% up to 10% is applied to the cellulose underpressure at temperatures between 170 degrees Celsius and 220 degreesCelsius for 0.0001 second up to 30 days in completing hydrolysis of all,or substantially all cellulose; above 50% hydrolysis of all cellulose.

In either acid combination described above, hydrolysis is augmented bythe optional application of shear, high shear or cavitation, whileadditional cellulose is added to the slurry to increase theconcentration of sugars.

Upon completion of cellulose hydrolysis, the slurry is either:

-   -   pH neutralized for use in downstream processes; or    -   boiled employing the drying process below with sugars separated        from the catalyst; where the catalyst is recycled and        recondensed using the drying process described below.

Cellulose Hydrolysis Using Concentrated Strong Acid

Unless otherwise noted, all number references within this section are toFIG. 3. In one embodiment, the method of reducing particles andpre-treating biomass in FIG. 1, [2]-[7], is applied. In this variant,small-dimension dry or high solids biomass fibres are introduced intolow boiling point strong acid and water at a low temperature, between 1degree Celsius and 118 degrees Celsius. The solution is maintained atwater ratios relative to the concentration of the strong acid catalystand to the net biomass in the proportions required to minimize the waterrequired to facilitate hydrolysis [9]. Mixing, or high-shear and/orcavitation are optionally applied at various time points during thisprocess as the biomass fibers hydrolyze FIG. 3 [9-2]. Additional dry ormostly dry fine biomass fibers, depending on water requirements forhydrolysis, are introduced continuously during the hydrolysis. Theresulting solution is maintained at viscosity sufficient for optimalhydrolysis rates and optimal yields, ideally above 80% concentration bymass. The viscosity should allow for mixing, FIG. 3 [8-2] and flowwithout pumping failure.

The high viscosity biomass hydrolysates slurry, which may consist ofacid, water, sugar, lignin, amino acids and minerals, is dried byapplying heat or, alternately, extracted and pumped to a high pressurezone. It may also be dried by being pressurized, then released into alower pressure zone while applying heat. It may be spray dried against asolid surface, or dried by applying pressure and optionally heatsufficiently high to provide for fast drying and degree of drying uponpressure release. Optionally, vacuum is also applied to reduce boilingtemperature of the add catalyst. The drying method described herein maybe employed to produce dry products.

Hydrolysate solids are mechanically scraped and moved into asolids-concentrating screw or other device which removes dry orpartially dried hydrolysates from the blow down zone and its heat.Hydrolysates, comprising sugar, lignin, amino acids and minerals, if notcompletely dried off of the volatile acid solution, are dried in a oneatmosphere dryer, or are introduced into a vacuum to lower boilingtemperature of the acid catalyst, with the acid catalyst being rapidlyboiled to produce a dry product. Acid vapors are condensed utilizingheat exchanger, including the drying design described herein.Alternately, volatile acid vapors are condensed onto new, unhydrolyzedbiomass.

Spray Drying Method in Both Hemicellulose, Lignin and Glucose ProductRecovery

In one drying and separation embodiment, the slurry extraction forboiling is pumped into a high pressure zone, where optionally acavitation device with, or without the recompression side of the device,or a high pressure spray nozzle, can be employed as a release method forslurry boiling. The slurry is then blown down to a lower pressure whileoptionally adding heal directly or indirectly. The slurry may beoptionally spray dried using spray drying systems known to those skilledin the art to facilitate drying. The resulting dry or substantially drysolids are rapidly scraped and removed into a separate zone for furtherlow pressure drying [14], or for dry product recovery [14-2]. In oneembodiment, a vacuum is applied to the extracted slurry in order tolower the boiling point of the liquid fraction in order to protecthydrolysis products.

Heat Exchange Drying and Recycling Method

With reference to FIG. 3, in one embodiment, a sugar solution near orjust below the boiling point of the solution is extracted fromhydrolysis system (304), consisting of sugar, catalyst and undissolvedbiomass solids. Mechanical pressure is applied through a belt press,plate and frame press, screw press, centrifuge or any type of solidliquid separation method known to those skilled in the art (303). Solidswith residual liquid are dried in biomass dryer (305). Additionalfiltration can be optionally applied to the liquid fraction expressedfrom the above described separation method to further clarify the liquidstream of solids.

The sugar solution passes through a heat exchanger through whichadditional heat is applied (302). Typically, heat is transferred from arecycled vapor from within the drying stage, optionally including acompressor prior to the heat exchanger to increase the pressure andtemperature of vapors (301). Instantly, the sugar solution enters anexpansion chamber, typically a double walled vessel (309) withcirculating oil or other fluid suitable for transporting heat at atemperature above the boiling point of the sugar solution. Optionally, aspinning shaft with blades rotates within the expansion chamber withblades operating close to the chamber walls to disperse and aid inremoval of liquid from sugars as they fall to the bottom of the chamber.Sugars and vapors are conveyed out of the expansion chamber into asolids-vapor separation zone (308) with vapors rising towards a heatexchanger (306), while sugars are further conveyed into a final sugardryer (307). Vapors going through the heat exchanger (308) exchange heatinto the expansion chamber's double wall to maintain a temperature abovethe boiling point of the incoming sugar solution, with the balance ofvapors continuing to an optional compressor (301) and/or the heatexchanger through which the incoming sugar solution is pumped.

Alternately, when applying concentrated strong, low boiling point acid,the boiling and drying method described above is employed to utilizeheat exchanger to conserve energy by exchanging boiling energyrequirements with condensing energy requirements to separate productfrom catalyst for re-use within the process.

Glucose Storage

Glucose, xylose, arabinose, galactose and other trace sugars, protein,amino acids, lignin, tannins, minerals and other trace biomass-derivedextractives produced by the present invention method can be stored incustom storage systems to prevent molding, insect, and animal problems.Systems are designed to receive large plastic bags containing glucose,with bags fitting tightly within the storage structure to minimize spacearound bags. Options for humidity, pest, and organic contaminationcontrol include small air conditioning systems, or vacuum to make insectlife impossible, gases, or other means of quality control for extendedtimeframes.

Biomass Feed

The term “biomass” includes any wet or dry organic matter (whole,fractions thereof, and/or any components thereof) available on arenewable basis, such as dedicated energy crops and trees, agriculturalfood and feed crops, agricultural crop wastes and residues, wood wastesand residues, aquatic plants, animal wastes, municipal solid wastes, rawsewage or post processing sewage solids, and other waste materials. Suchbiomass materials can serve as raw materials for the process of thepresent invention. Additional examples of relevant sources of biomassinclude, but are not limited to, cellulose-containing materials such ascorn-fibre, hay, sugar cane bagasse; starch-containing cellulosicmaterial such as grain, crop residues, newsprint, paper, sewage sludge,aquatic plants, sawdust, yard wastes; components thereof, fractionsthereof, and any other raw materials or biomass materials known to thoseof skill in the art. Lignocellulose-containing fibre can potentially berefined into sugars, protein, lignin and chemicals.

In general, the term “biomass” as used herein can include anycarbon-based materials. Biomass can therefore include, withoutlimitation, trees, grass, straw, grain husks, stalks, stems, leaves,aquatic plants such as water hyacinths, duckweed, paper, wood, etc.Preferably, the material of greatest use is a grass. Examples of grassesinclude, but are not limited to, Axonopus affinis and Axonopuscompressus, centipede grass (Eremochloa ophiuroides), buffalo grass(Buchloe dactyloides), hurricane grass also called Seymour grass(Bothriochloa pertusa), and seashore paspalum (Paspalum vaginatum).Other grasses that can be used include Poa, P. schlstacea, P. xenica,Deyeuxie lacustris, Dichelachne lautumia, Brachiaria Mutica, accorus,andropogon, carex, festuca, glyceria, molina, panicum, phalaris,spartina, sporobolus and miscanthus.

Other types of biomass employable in the process include: any type ofbiomass derived from processing, such as oat or rice hulls, canning foodwaste or other refining or processing waste; straw, corn stover ornative biomass of any type that is collected loose, baled, ensiled,piled or in any other configuration commonly employed in agriculture orharvest; raw sewage solids or post-processing sewage sludge, dry or wet,collected at any concentration from a sewage plant; filtration of raw,unsettled sewage can be applied in some embodiments of the invention toconcentrate solids; aquatic plants such as algae and water hyacinths orany type of aquatic plants.

Types of Slurry Equipment Used in the Present Invention

There are a number of machines that can be used to mechanically reducethe particle size of biomass.

One optional means for processing large biomass particles into smallerparticles in a slurry are “conical fools” (e.g. Supraton™ Conical Tool).In the Supraton™ device, the rotor is bolted onto a shaft and the statoris bolted into the end plate, but different models or brands can employdifferent types of internal system configurations. Generally, conicaltools are a set of rotor-stators of two cone-shaped internal wettedcomponents with matching indented faces. Adjustable, small distancepassages exist between the two faces, with one rotor which moves, andone stationary stator component. Together, the components create shearas a biomass slurry enters the system and is then forced centrifugallybetween the two faces due to any upstream external and the Supraton'spumping centrifugal force. Larger biomass particles are shredded andtorn, resulting in smaller particles.

Many other types and brands of slurry shear and cavitation processmachines are known to those skilled in the art, including IKA, IKA HED,Sllverson, Greerco, Arisdyne, Cavitation Technologies, Inc., and others.Alternately or in combination with the conical tools design, an HED typeof “slurry-grinder” pump with a single rotor and and a single statorscreen, the stator screen with custom screen hole sizes as large as 50millimeters in diameter, to as small as 0.25 millimeters, is applied tofurther reduce biomass particle size without cavitational forces. Such agrinder pump produces little if any cavitation, but does produce shearforces in which water flow of a slurry is violently split to reduceparticle size, and can be made more intense due to smaller hole sizes inthe stator.

Any shear or cavitation device can be applied multiple times to achievespecific results in mechanical particle size reduction, or incombination with chemical catalysts and heat to achieve different ratesand degrees of hydrolysis, including quantitative hydrolysis, and toachieve cell disruption to enhance mechanical liquid extraction.Examples of cavitation devices useful in the present invention are thosemanufactured by BWS, Cavitation Technologies, Inc., Arisdyne or anyother manufacturer's machine which can be employed to create cavitation.Some cavitation devices can utilize holes as small as 0.25 millimetersto create different levels of cavitation shear. In cavitation deviceswith intermeshing rotor-stator design, feet per second rates of rotorrotation can range from 50 feet per second to 400 feet per second.Cavitation is created by inducing pressure through pumping action of arotor at the entry side of holes in rotor-stator design, with a lowerpressure on the exit side of the hole, or a single hole in a pump andnozzle design. Single nozzle tools are a variation of rotor statormachines in that pressure above the nozzle entrance is created in aseparate position within the machine from the single nozzle. Any type ofcavitation device can optionally be used in the present inventiondepending on specific process requirements and advantages of aparticular machine. Combinations of cavitation machine types can beoptionally be employed, including for example in drying strategies.

1-49. (canceled)
 50. A process for refining biomass, the processcomprising the steps of: a. performing a first hemicellulose hydrolysisby: (i) forming a first slurry from the biomass having a first solidsportion comprising hemicellulose and cellulose, and having a firstliquid portion; (ii) adding an alkaline catalyst and applying heat andeither mechanical shear or cavitation to the first slurry; (iii)mechanically separating the first solids portion from the first liquidportion; (iv) combining the first liquid portion with additional biomassand repeating steps (a)(ii) and (a)(iii) until at least a 7%concentration of extractable products in the first slurry is achieved;and (v) recovering the extractable products from the first slurry; andb. performing a second hemicellulose hydrolysis by: (i) combining thefirst solids portion and an acid catalyst in a second slurry having asecond solids portion, and a second liquids portion comprisinghemicellulose hydrolyzates in solution, and applying mechanical shear orcavitation to the second slurry resulting in hydrolysis of thehemicellulose and producing additional acid catalyst; (ii) mechanicallyseparating the second solids portion from the second liquid portion;(iii) recovering the acid catalyst from the second liquid portion; and(iv) repeating steps (b)(i) and (b)(ii), using, in step (b)(i), thesecond solids portion recovered in step (b)(ii) as the first solidsportion and the catalyst recovered in step (b)(iii), adding additionalcatalyst to maintain a minimum specified concentration of acid catalystand maintain a sugar product concentration of at least 7%, until all orsubstantially all hemicellulose is hydrolyzed.
 51. The process of claim50, wherein the second solids portion comprises lignin, furthercomprising the steps of c. drying the second solids portion comprisingcellulose-lignin microfibres; d. hydrolyzing the lignin in the secondsolids portion in an alkaline catalyst solution by applying mechanicalshear or cavitation; and e. mechanically separating the liquid portionof the hydrolyzed lignin from the second solids portion.
 52. The processof claim 51, wherein step of hydrolyzing lignin is repeated toconcentrate the lignin in solution before step of mechanical separationand all or substantially all lignin is liquefied.
 53. The process ofclaim 50, wherein any one of steps a., b., and c, and any combinationthereof, takes place at atmospheric pressure.
 54. The process of claim50, wherein weak acid concentration in solution is in the range from0.001% to 90% by volume, and at least one other strong acidconcentration in solution is in the range from 0.001% to 3% by volume.55. The process of claim 50, wherein step b. or c, takes place above 0°C. and below 118° C.
 56. The process of claim 50, wherein a weak acid isadded in solution to a concentration of between 60% and 80% by volume.57. The process of claim 54, wherein the at least one other strong acidis present in a concentration between 0.001% and 1% by volume.
 58. Theprocess of claim 51, further comprising the step of: f. hydrolyzingcellulose in the second solids portion in the presence of at least onestrong acid to produce solution comprising sugar.
 59. The process ofclaim 58, wherein step b. iv) is repeated, to raise the concentration ofthe sugar in the solution comprising sugar to greater than 15% by mass.60. The process of claim 59, further comprising drying the solutioncomprising sugar.
 61. The process of claim 58, wherein the sugarcomprises glucose.
 62. The process of claim 51, further comprisingdrying the second solids portion to remove moisture and the weak acid toproduce dry cellulose.
 63. The process of claim 50, wherein acetic acidis produced as a product of hydrolysis, and is recovered and used as thecatalyst.
 64. The process of claim 51, wherein the alkaline catalystintroduced in step d is reclaimed and used to hydrolyze hemicellulose instep a (ii) of claim 50.